Generally yes, and I won’t get into the weeds about how inlined methods can have their inlinedness invalided if you look too hard at or breathe on them- but this isn’t a deterministic process. The first time you touch an ActiveRecord::Model, the database is queried and your classes ARE redefined. It’s not even close to the same ballpark of loading a new class on the JVM, and the stabilizing assumption you’re hoping exists often doesn’t. Death by 1,000 cuts